η-η' mixing in η-mesic nuclei

Abstract

η bound states in nuclei are sensitive to the flavour-singlet component in the η. The bigger the singlet component, the more attraction and the greater the binding. η-η′ mixing plays an important role in understanding the value of the η-nucleon scattering length a ηN. Working with the Quark Meson Coupling model, we find a factor of two enhancement from mixing relative to the prediction with a pure octet η.